Nutrient Management Research Database

Field studies to determine the effect of different rates of fertilization on emission of nitrous oxide (N₂O) from soil fertilized with anhydrous ammonia showed that the fertilizer-induced emission of N₂O-N in 116 days increased from 1.22 to 4.09 kg ha⁻¹ as the rate of anhydrous ammonia N application was increased from 75 to 450 kg ha⁻¹. When expressed as a percentage of the N applied, the fertilizer-induced emission of N₂O-N in 116 days decreased from 1.6% to 0.9% as the rate of fertilizer N application was increased from 75 to 450 kg N ha⁻¹. The data obtained showed that a 100% increase in the rate of application of anhydrous ammonia led to about a 60% increase in the fertilizer-induced emission of N₂O.

Field studies to determine the effect of depth of fertilizer injection on emission of N₂O from soil fertilized with anhydrous ammonia showed that the emission of N₂O-N in 156 days induced by injection of 112 kg anhydrous ammonia N ha⁻¹ at a depth of 30 cm was 107% and 21 % greater than those induced by injection of the same amount of N at depths of 10 cm and 20 cm, respectively. The effect of depth of application of anhydrous ammonia on emission of N₂O was less when this fertilizer was applied at a rate of 225 kg N ha⁻¹.

This study investigated how depth of injection influenced nitrous oxide (N2O) emissions from anhydrous ammonia (AA) fertilization.

Anhydrous ammonia was injected at the rate of 100 or 200 lbs N/ac at a depth of either 4, 8, and 12 inches.

N2O emissions were measured for 156 days following fertilization.

N₂O emissions increased with increased rate of fertilization.

N₂O emissions were lowest when AA was injected at 12 inches, and increased as the depth of injection decreased. This reflects the ability of soil microbes to consume N₂O before it reaches the soil surface and is emitted into the atmosphere.

This study did not measure ammonia volatilization, which can be elevated when AA is injected closer to the soil surface.